writing ,drawing ,scratching on the wall

i work in the construction trade.so most of the time the bathroom facilities i use at work are not very nice .wal-mart has great bathrooms compared to the port-o lets we get to use .one thing that you find on most jobs is lots of writing and graffiti on the walls of the port-o-lets .some writings are about who is the biggest suck-ass .or which Foreman is the biggest jerk,crackhead,idiot ect....getting close to Superbowl earlier in the year there was lots of writing about the saints on the walls. but one thing that is always a steady favorite of the walls is drawings or depictions of naked ladies ,phallic symbols ,male /female engaged in various sexual acts .and yes even some drawings of male/male sex acts .i often wonder are these put up for fun or is this all some people think on .and in turn they think other people might enjoy what they keep their minds on. i went into a port o let today and one of our artist had taken a knife or other sharp object and scratched a drawing on top of the commode lid .it was a well done piece of art ,there were no hesitation marks no excess scratches .this guy had done this before and truly had a vision of what he was presenting. but i wonder why they feel the need to trash the walls up .i truly love to walk into a place that has clean bathroom ,no filth on the floors or the walls. if you work in place that the bathroom is not all trashed you are blessed.